Reproducibility Of Experimental Results Research Articles

Minerals Dissolution Effect on the Mechanical Properties of Synthetic Carbonate Rocks

Injection of CO2 and water in saline aquifers or oil reservoirs causes changes of pressure, saturation and concentrations that affect the state of stress and promote chemical reactions in the host rock, resulting in porosity and permeability variations. It is therefore a coupled hydro-mechanical and chemical (HMC) problem. Numerical simulation of multiphase and multicomponent flow of CO2, oil and water with mechanical coupling allows realistic modeling of the reservoir and cap rocks. Carbonate reservoirs are geological formations composed mainly of minerals such as calcite and dolomite which can dissolve or precipitate in the medium when injecting a fluid of chemical composition and temperature different from those of the fluids initially contained in the rock. Water-weakening due to matrix acidification of carbonates is a well-known phenomenon that can be modeled by including mineral concentrations as state variables in the stress-strain behavior of the material.
 The objective of this work is to characterize synthetic carbonate rocks through microtomography and petrography techniques, focusing on a comparative analysis before and after load application and degradation with a reactive fluid [1]. The synthetic rocks were subjected to physical characterization (mineralogy, computed tomography and porosity) and mechanical characterization (uniaxial compressive strength and Brazilian tests) before and after the dissolution process. The petrographic analysis verified an increase in both intergranular and intragranular porosities after dissolution. The microtomography analysis quantified the maximum increase in porosity, from 11.8% to 41.3% in the two-dimensional analysis and 31.6% to 52% in the three-dimensional analysis of the porous structures. Furthermore, the pores were quantified according to their area, and data was obtained on the orientation of the pores, providing insight into the preferred paths of fluid flow. It was also observed that the microtomography technique was an effective tool for characterizing fractures in the samples before and after dissolution [1].
 Dissolution tests were also performed in a modified oedometer cell adapted to measure horizontal stress. The dissolution phase was conducted using water and an acid solution to evaluate the influence of the pH on the mechanical behaviour of the samples. When the sample in the oedometric cell is exposed to an acid solution under constant vertical load of 400kPa, vertical displacement takes place (volume decrease of the sample) and horizontal stress increases (Figure 1). The synthetic rock used in this experiment is mainly composed by calcite, with small additions of calcium hydroxide, and the reactive fluid is water acidified with acetic acid (with 10% concentration). This material is manufactured in laboratory in order to have greater control of its constituents and reproducibility of experimental results. During the acidification phase of the experiment, the sample was subjected to an acid flow with a pressure differential of 12kPa for 7h. The behavior in Figure 1 was also observed by [2] and [3]. The model for degradation of carbonatic soft rocks proposed by [2] was implemented in a finite element code capable of performing coupled THMC analyzes in porous media [4]. This model is based on the Critical State Theory with the introduction of a bonding variable that controls the size of the yield surface by modifying the tensile strength and the pre-consolidation stress of the material. In Figure 1 it is also possible to see that the HMC coupled simulation of the oedometric test was able to reproduce the experimental results in terms of volumetric strain and horizontal stress. In Figure 2 tomographic images of the synthetic carbonate rock before and after exposure to the acid solution in an oedometric cell under constant vertical load are presented. Such analyses are crucial for the injection of reactive fluids, such as CO2, at high depths. Dissolution of minerals will affect not only the porosity and permeability of the reservoir rock but also, possibly, the stress state in the vicinity of the injection well.

MISM: A Medical Image Segmentation Metric for Evaluation of Weak Labeled Data.

Performance measures are an important tool for assessing and comparing different medical image segmentation algorithms. Unfortunately, the current measures have their weaknesses when it comes to assessing certain edge cases. These limitations arise when images with a very small region of interest or without a region of interest at all are assessed. As a solution to these limitations, we propose a new medical image segmentation metric: MISm. This metric is a composition of the Dice similarity coefficient and the weighted specificity. MISm was investigated for definition gaps, an appropriate scoring gradient, and different weighting coefficients used to propose a constant value. Furthermore, an evaluation was performed by comparing the popular metrics in the medical image segmentation and MISm using images of magnet resonance tomography from several fictitious prediction scenarios. Our analysis shows that MISm can be applied in a general way and thus also covers the mentioned edge cases, which are not covered by other metrics, in a reasonable way. In order to allow easy access to MISm and therefore widespread application in the community, as well as reproducibility of experimental results, we included MISm in the publicly available evaluation framework MISeval.

Methanol-Based Whole-Mount Preparation for the Investigation of Retinal Ganglion Cells

Retinal ganglion cells (RGCs), which are the projection neurons of the retina, propagate external visual information to the brain. Pathological changes in RGCs have a close relationship with numerous retinal degenerative diseases. Whole-mount retinal immunostaining is frequently used in experimental studies on RGCs to evaluate the developmental and pathological conditions of the retina. Under some circumstances, some valuable retina samples, such as those from transgenic mice, may need to be retained for a long period without affecting the morphology or number of RGCs. For credible and reproducible experimental results, using an effective preserving medium is essential. Here, we describe the effect of methanol as an auxiliary fixed medium for retinal whole-mount preparations and long-term storage. In brief, during the isolation process, cold methanol (-20 °C) is pipetted onto the surface of the retina to help fix the tissues and facilitate their permeability, and then the retinas can be stored in cold methanol (-20 °C) before being immunostained. This protocol describes the retina isolation workflow and tissue sample storage protocol, which is useful and practical for the investigation of RGCs.

BEST: Building evidences from scattered templates for accurate contactless palmprint recognition

Contactless palmprint identification offers significantly improved hygiene and user convenience, making it highly attractive for a range of civilian applications, especially during the current pandemic. However, the accurate recognition of contactless palmprint images can be highly challenging, attributed to the significant variations in the intra-class similarity and limitations of conventional palmprint feature descriptors under involuntary or contactless imaging variations. State-of-the-art completely contactless palmprint matching algorithms in the literature cannot adequately address these challenges and are not sufficiently accurate and fast enough for such real-world applications. This paper proposes a novel approach that adaptively locates the local palmprint regions with high similarities between their corresponding feature representations or templates to address these challenges. We consider spatial localization of such highly similar feature representations from multiple local regions and consolidate them to generate a more reliable match score. This paper presents reproducible and comparative experimental results, using within-database, cross-database, and cross-sensor performance evaluation, on four publicly available contactless palmprint datasets, including a sizeable contactless palmprint database from 600 different subjects. The proposed method achieves outperforming results compared with three state-of-the-art deep learning-based methods and five widely used conventional methods. In addition, the proposed method is also significantly faster than all state-of-the-art baseline methods.

Assessing the generalisability of radiomics features previously identified as predictive of radiation-induced sticky saliva and xerostomia.

While core to the scientific approach, reproducibility of experimental results is challenging in radiomics studies. A recent publication identified radiomics features that are predictive of late irradiation-induced toxicity in head and neck cancer (HNC) patients. In this study, we assessed the generalisability of these findings. The procedure described in the publication in question was applied to a cohort of 109 HNC patients treated with 50-70Gy in 20-35 fractions using helical radiotherapy although there were inherent differences between the two patient populations and methodologies. On each slice of the planning CT with delineated parotid and submandibular glands, the imaging features that were previously identified as predictive of moderate-to-severe xerostomia and sticky saliva 12months post radiotherapy (Xer12m and SS12m) were calculated. Specifically, Short Run Emphasis (SRE) and maximum CT intensity (maxHU) were evaluated for improvement in prediction of Xer12m and SS12m respectively, compared to models solely using baseline toxicity and mean dose to the salivary glands. None of the associations previously identified as statistically significant and involving radiomics features in univariate or multivariate models could be reproduced on our cohort. The discrepancies observed between the results of the two studies delineate limits to the generalisability of the previously reported findings. This may be explained by the differences in the approaches, in particular the imaging characteristics and subsequent methodological implementation. This highlights the importance of external validation, high quality reporting guidelines and standardisation protocols to ensure generalisability, replication and ultimately clinical implementation.

LiverQuant: An Improved Method for Quantitative Analysis of Liver Pathology.

Current means to quantify cells, gene expression, and fibrosis of liver histological slides are not standardized in the research community and typically rely upon data acquired from a selection of random regions identified in each slide. As such, analyses are subject to selection bias as well as limited subsets of available data elements throughout the slide. A whole-slide analysis of cells and fibrosis would provide for a more accurate and complete quantitative analysis, along with minimization of intra- and inter-experimental variables. Herein, we present LiverQuant, a method for quantifying whole-slide scans of digitized histologic images to render a more comprehensive analysis of presented data elements. After loading images and preparing the project in the QuPath program, researchers are provided with one to two scripts per analysis that generate an average intensity threshold for their staining, automated tissue annotation, and downstream detection of their anticipated cellular matrices. When compared with two standard methodologies for histological quantification, LiverQuant had two significant advantages: increased speed and a 50-fold greater tissue area coverage. Using publicly available open-source code (GitHub), LiverQuant improves the reliability and reproducibility of experimental results while reducing the time scientists require to perform bulk analysis of liver histology. This analytical process is readily adaptable by most laboratories, requires minimal optimization, and its principles and code can be optimized for use in other organs. Graphical overview.

Detecting Locally, Patching Globally: An End-to-End Framework for High Speed and Accurate Detection of Fingerprint Minutiae

Billions of fingerprint images are acquired and matched to protect the national borders and in a range of egovernance applications. Fast and accurate minutiae detection from fingerprint images is the key to advance fingerprint matching algorithms for large-scale applications. However, currently available fingerprint minutiae extraction methods are not accurate and fast enough to support such large-scale applications. This paper proposes a new method that uses a lightweight pixelwise local dilated neural network to extract local features and a patch-wise global neural network to recover the global features. It consolidates the local and global fingerprint features to generate a full-size minutiae location map, and then accurately localizes the minutiae positions by using a recursive connected components algorithm. We design a new loss function to accurately detect minutia orientation and incorporate a dynamic end-to-end loss to provide effective supervision in learning discriminant features. It is due to the proposed design and loss function that can enable higher accuracy with significantly less computations. We present reproducible experimental results from five publicly available contact-based and contactless databases that indicate significant improvement in the minutiae detection accuracy, which also leads to enhanced fingerprint matching accuracy. Since the minutiae represent key points in the fingerprint images, the proposed end-to-end minutiae detection method also has a potential to be employed in many other key points detection tasks.

Near-edge x-ray absorption and emission of cyanates and thiocyanates

The comparability and reliability of the analysis of the electronic structure of selected cyanates and thiocyanates at the nitrogen $K$ edge based on BSE calculations have been investigated in this work. Using high-resolution x-ray spectroscopy with calibrated instrumentation reliable and reproducible experimental results for x-ray absorption spectroscopy (XAS) and resonant inelastic x-ray scattering (RIXS) were achieved. These results were used to validate theoretical modeling with first-principles calculations based on the Bethe-Salpeter equation approach for the excited-state interactions. Furthermore, radiation-induced damages occurring in the samples are correlated with absolute doses.

The Theory of the Existence of the "Mental Body in Matter" Based on the Experimental Laboratory Results and Taheri Consciousness Fields

The present study aimed to investigate the mechanism of effects of TaheriConsciousness Fields (TCFs) on the properties and behavior of materials usingthe previous experimental results in this field. By reviewing the existingevidence from the recent laboratory test results, a novel theory of the TCFsarises. The emergence of different properties and behavior of materials inthe presence of the TCFs suggests that matter, in addition to the physicalbody (its constituent matter and energy), necessarily needs a “mental body”.According to this theory, the mental body of matter includes information oneach component of the system, the process of formation, and all its equilibriumand unbalanced states, and mental states that were formed during theprocess of the formation of matter, and its equilibrium state. The functionof the mental body of matter is to maintain the information, to interact withthe TCFs, to accept new mental states, and to exhibit behavior appropriateto the new mental state. According to this theory, which is completely basedon the reproducible experimental laboratory results, the effects of the TCFscan be observed from two distinct aspects: TCFs and Matter. In the formeraspect, it is equivalent to the application of one of the mental states in thecoordinates of the mind of matter. In the latter aspect, this is equivalent tothe occurrence of a behavior corresponding to the nature of matter experiencedthrough evolution. In addition, this process takes place without givingor taking energy or changing the microstructure or arrangement of the matter.Moreover, this study explains why and how the properties and behaviorof materials were changed under the influence of the TCFs while these Fieldsdid not lead to a decrease or increase in the energy level of matter or changein the structure of matter.

Technical Note: Methodology Development to Study Two-Dimensional Stainless Steel Pitting Corrosion Mechanisms Using Foil Samples

In this Technical Note, four foil sample preparation methodologies were investigated with “sandwich” like foil electrodes, which enabled the visualization of two-dimensional pit morphologies. The new procedure included the use of nitric acid to prepassivate the foil as the first step; polishing the top layer of the side edges of the foil after the foil was sandwiched in between two glass slides; and immersing the corners in nitric acid before experiments. This new foil sample preparation methodology eliminated pitting artifacts at the corners of the foil samples and provided reliable and reproducible experimental results.

Precise and Dynamic Temperature Control in High-Resolution Microscopy with VAHEAT

Abstract:Temperature is a key parameter in most biological and physical systems. It is, however, an inherent technological challenge to precisely track and control the temperature of small sample volumes when using high- and super-resolution microscopes. Various effects can cause a deviation of the sample temperature from its expected value, specifically in the observed volume or field-of-view. These effects include direct thermal contact of the objective lens and the coverslip via immersion medium, illumination-induced heating, evaporative cooling, or triggered phase transitions. In this paper, we shed light on these phenomena and introduce our newly developed device VAHEAT, which follows a microscopic approach for controlling and measuring the sample temperature. Our system overcomes traditional limitations of temperature sensing and controlling in high-sensitivity microscopy applications, leading to more reproducible experimental results and conquering new experimental parameter ranges.

USE OF ANALYSIS TECHNIQUE FOR IMMOBILIZED YEAST SACCHAROMYCES CEREVISIAE IN THE BIOTECHNOLOGICAL INDUSTRY

Article is devoted to the current state and problems of microbial cells immobilization and also prolonged storage of immobilized cells systems for the aims of biotechnological industry.
 In the experimental part immobilization conditions for the cells S. cerevisiae in alginate gel and vitality test, which had given high reproducibility of experimental results, were developed.
 Experimental results showed that viability of immobilized cells was higher than that of free yeast cells. It is possible that gel matrix has a protective effect on yeast cells during freezing.
 Comprehensive effect of cooling modes and preservation protective mediums, which contain sodium alginate, on viability of yeasts has been investigated. Advantage of yeast cells storage in immobilized state was shown experimentally. It was found that cooling mode and composition of preservation medium affect on the viability of S. cerevisiae cells during cryopreservation. In all freezing medium, both without protective components and with addition of a cryoprotective agent, the best results were obtained with cooling at a rate of 1°C/min. Viability indices in the samples were: 73.1 % – in distilled water; 90.8 % – in 1 % sodium alginate solution; 87.1 % – in 5 % DMSO solution and 86.1 % – in 1 % sodium alginate solution with the addition of 5 % DMSO. When cells were frozen in a 5 % DMSO solution and in a 1 % sodium alginate solution with the addition of 5 % DMSO, number of viable cells also decreased as cooling rate increased, but, probably, did not differ from the cell viability index in those samples that were frozen in 1 % sodium alginate solution. The highest results of viability for S. cerevisiae yeast cells were obtained during slow cooling for all cryoprotective mediums. For the first time, high cryoprotective properties of sodium alginate solution, were shown.
 Obtained results are enable to recommend the sodium alginate as a carrier for cryopreserved immobilized cells when using it in biotechnological processing for biologically active substances production.

Statics simulation of the sulphate iron-containing wastewater neutralization process

At the present stage of technical progress, all industries face an extremely complex problem of creating reliable barriers that prevent the penetration of industrial emissions into the environment. Currently, the issues of stabilizing the quality of wastewater treatment have become especially important in connection with the task of developing wastewater-free industrial complexes. Among the complex scientific and technical problems associated with this task, the problem of stable and reliable maintenance of water quality parameters at the outlet of technological systems is crucial, as leakage of pollutants immediately affects the state of basic production, disrupting its technology and infecting ecosystems.
 The focus of industry on a sharp reduction in emissions and on the creation of industrial cycles with circulating water supply requires intensive efforts to improve the wastewater treatment technology, the introduction of high-performance processes and devices, as well as the synthesis of control systems for typical wastewater treatment processes. 
 For the performance of automated control systems for typical cleaning processes, it is necessary to develop a software package on the basis of appropriate mathematical models of typical processes. To obtain them, methods of mathematical and simulation modeling and variance analysis were used.
 In order to assess the quality of modeling, the presented mathematical model describing the statics of the neutralization process for ferrous sulfate water was tested for compliance. To do this, two experiments were performed (the first at an initial concentration of sulfuric acid of 800 [mg/l] and ferrous sulfate of 4000 [mg/l] and the second at an initial concentration of sulfuric acid of 800 [mg/l] and ferrous sulfate of 2000 [mg/l]). First of all, a precondition for the reproducibility of experimental results was verified using the Cochrane test. The mathematical model was verified for adequacy on the basis of Fisher's criterion for the significance level q = 0.05 with degrees of freedom j1 = 16 and j2 = 17.
 For the first experiment, Grozr = 0.50557 and Gmab = 0.73; i.e., Grozr < Gmab and dispersions are homogeneous. Frozr = 1.0225 and Fmab = 2.4 and thus Frozr < Fmab, and there is no reason to say that the model is inadequate.
 For the second experiment, Grozr = 0.50308 and Gmab = 0.73; i.e., Grozr < Gmab and dispersions are also homogeneous. Frozr = 1.0005 and Fmab = 2.4 and thus Frozr < Fmab, which also indicates that the model is adequate.
 The issue related to the performance of technological systems for wastewater treatment in non-stationary modes is directly dictated by the specific operating conditions of treatment facilities, which are expressed by the instability of parameters at their inlet. The inability to apply the necessary technological action to the flow in time is a serious obstacle to the implementation of the cleaning depth, which is guaranteed by the physicochemical basis of the methods incorporated in technological systems and requiring cleaning standards. The operator cannot handle this complex task manually. On the basis of the proposed mathematical model, a structural-parametric diagram of the automated process control system has been developed, which makes it possible to proceed to the elaboration of algorithms and software for the control system necessary for automated control of the wastewater treatment process.

Разработка инновационных материалов для судебной экспертизы

In the production of experimental studies related to the modeling of the behavior of human soft tissues in such widespread types of forensic examinations as forensic ballistic, tracological, forensic examination of cold and throwing weapons, forensic medical-use bioimitators. Human corpses, animal carcasses, and their living individuals are used as such objects, but in recent decades, with the development of chemistry and chemical technology, various artificial substitutes have become increasingly widespread – colloidal systems based on gelatin, soap, mixtures of petroleum petrolatum, as well as specialized compositions. Among the main advantages of using soft tissue substitutes are the following: visibility of the results obtained, availability of synthetic materials, uniformity of structure, reproducibility of experimental results with a statistically reliable amount, as well as, if necessary, the possibility of varying mechanical parameters for physical modeling of the characteristics of human biological tissues within the framework of an expert experiment. The paper proposes a technology for obtaining a reusable synthetic compound that allows modeling the properties of human soft tissues. The synthetic compound provides the transfer of general patterns of morphology of the formed gunshot injuries, similar to gunshot wounds on biological materials.

Improving reproducibility in synchrotron tomography using implementation-adapted filters.

For reconstructing large tomographic datasets fast, filtered backprojection-type or Fourier-based algorithms are still the method of choice, as they have been for decades. These robust and computationally efficient algorithms have been integrated in a broad range of software packages. The continuous mathematical formulas used for image reconstruction in such algorithms are unambiguous. However, variations in discretization and interpolation result in quantitative differences between reconstructed images, and corresponding segmentations, obtained from different software. This hinders reproducibility of experimental results, making it difficult to ensure that results and conclusions from experiments can be reproduced at different facilities or using different software. In this paper, a way to reduce such differences by optimizing the filter used in analytical algorithms is proposed. These filters can be computed using a wrapper routine around a black-box implementation of a reconstruction algorithm, and lead to quantitatively similar reconstructions. Use cases for this approach are demonstrated by computing implementation-adapted filters for several open-source implementations and applying them to simulated phantoms and real-world data acquired at the synchrotron. Our contribution to a reproducible reconstruction step forms a building block towards a fully reproducible synchrotron tomography data processing pipeline.

Wafer-scale integration of graphene for waveguide-integrated optoelectronics

As the focus of graphene research shifts from fundamental physics to applications, the scalability and reproducibility of experimental results become ever more important. Graphene has been proposed as an enabling material for the continuing growth of the telecommunications industry due to its applications in optoelectronics; however, the extent of its adoption will depend on the possibility to maintain the high intrinsic quality of graphene when processing it using the industry-standard approaches. We look at the challenges of scalable graphene integration and the opportunities presented by the recent technological advances.

Membrane Surface Functionalization with Imidazole Derivatives to Benefit Dye Removal and Fouling Resistance in Forward Osmosis.

Water contaminated with low concentrations of pollutants is more difficult to clean up than that with high pollutant content levels. Membrane separation provides a solution for removing low pollutant content from water. However, membranes are prone to fouling, losing separation performances over time. Here we synthesized neutral (IM-NH2) and positively charged (IL-NH2) imidazole derivatives to chemically functionalize membranes. With distinct properties, these imidazole grafts could tailor membrane physicochemical properties and structures to benefit forward osmosis (FO) processes for the removal of 20-100 ppm of Safranin O dye-a common dye employed in the textile industry. The water fluxes produced by IM-NH2- and IL-NH2-modified membranes increased by 67% and 122%, respectively, with DI water as the feed compared to that with the nascent membrane. A 39% flux increment with complete dye retention (∼100%) was achieved for the IL-NH2-modified membrane against 100 ppm of Safranin O dye. Regardless of the dye concentration, the IL-NH2-modified membrane exhibited steadily higher permeation performance than the original membrane in long-term experiments. Reproducible experimental results were obtained with the IL-NH2-modified membrane after cleaning with DI water, demonstrating the good antifouling properties and renewability of the newly developed membrane.

Development and Quantitation of Pseudomonas aeruginosa Biofilms after in vitro Cultivation in Flow-reactors.

Characterization of biofilm formation and metabolic activities is critical to investigating biofilm interactions with environmental factors and illustrating biofilm regulatory mechanisms. An appropriate in vitro model that mimics biofilm in vivo habitats therefore demands accurate quantitation and investigation of biofilm-associated activities. Current methodologies commonly involve static biofilm setups (such as biofilm assays in microplates, bead biofilms, or biofilms on glass-slides) and fluidic flow biofilm systems (such as drip-flow biofilm reactors, 3-channel biofilm reactors, or tubing biofilm reactors). Continuous flow systems take into consideration the contribution of hydrodynamic shear forces, nutrient supply, and physical transport of dispersed cells, which define the habitat for biofilm development in most natural and engineered systems. This protocol describes the assembly of 3 flow-system setups to cultivate Pseudomonas aeruginosa PAO1 and Shewanella oneidensis MR-1 model biofilms, including the respective quantitation and observation approaches. The standardized flow systems promise productive and reproducible biofilm experimental results, which can be further modified according to specific research projects.

Effects of weaning age and housing conditions on phenotypic differences in mice

Poor reproducibility is considered a serious problem in laboratory animal research, with important scientific, economic, and ethical implications. One possible source of conflicting findings in laboratory animal research are environmental differences between animal facilities combined with rigorous environmental standardization within studies. Due to phenotypic plasticity, study-specific differences in environmental conditions during development can induce differences in the animals’ responsiveness to experimental treatments, thereby contributing to poor reproducibility of experimental results. Here, we studied how variation in weaning age (14–30 days) and housing conditions (single versus group housing) affects the phenotype of SWISS mice as measured by a range of behavioral and physiological outcome variables. Weaning age, housing conditions, and their interaction had little effect on the development of stereotypies, as well as on body weight, glucocorticoid metabolite concentrations, and behavior in the elevated plus-maze and open field test. These results are surprising and partly in conflict with previously published findings, especially with respect to the effects of early weaning. Our results thus question the external validity of previous findings and call for further research to identify the sources of variation between replicate studies and study designs that produce robust and reproducible experimental results.

The Identity of Organisms in Scientific Practice: Integrating Historical and Relational Conceptions.

We address the identity of biological organisms at play in experimental and modeling practices. We first examine the central tenets of two general conceptions, and we assess their respective strengths and weaknesses. The historical conception, on the one hand, characterizes organisms' identity by looking at their past, and specifically at their genealogical connection with a common ancestor. The relational conception, on the other hand, interprets organisms' identity by referring to a set of distinctive relations between their parts, and between the organism and its environment. While the historical and relational conceptions are understood as opposed and conflicting, we submit that they are also fundamentally complementary. Accordingly, we put forward a hybrid conception, in which historical and relational (and more specifically, organizational) aspects of organisms' identity sustain and justify each other. Moreover, we argue that organisms' identity is not only hybrid but also bounded, insofar as the compliance with specific identity criteria tends to vanish as time passes, especially across generations. We spell out the core conceptual framework of this conception, and we outline an original formal representation. We contend that the hybrid and bounded conception of organisms' identity suits the epistemological needs of biological practices, particularly with regards to the generalization and reproducibility of experimental results, and the integration of mathematical models with experiments.